Webcams used to be just for checking weather at the beach and Skyping with your in-laws. Now Internet cameras can easily record everything that happens around the house—they're your domestic all-seeing eyes.

This may sound a bit creepy. But there's a certain appeal to do-it-yourself home security: My San Francisco neighborhood has had a spate of burglaries, and I'd love an inexpensive and simple way to know if someone is at my window...